sim/ppc: Add ATTRIBUTE_PRINTF

Clang generates a warning if the format string of a printf-like function is
not a literal ("-Wformat-nonliteral").  On the default configuration, it
causes a build failure (unless "--disable-werror" is specified).

To avoid warnings on the printf-like wrapper, it requires proper
__attribute__((format)) and we have ATTRIBUTE_PRINTF macro for this reason.

This commit adds ATTRIBUTE_PRINTF to the printf-like functions.

For the error function defined in sim_calls.c, the ATTRIBUTE_NORETURN
has been moved to the function declaration.

sim/ppc/misc.h

@@ -30,8 +30,8 @@
 #include "ansidecl.h"
 #include "filter_filename.h"
 
-extern void error
-(const char *msg, ...);
+extern void error (const char *msg, ...)
+  ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (1, 2);
 
 #define ASSERT(EXPRESSION) \
 do { \
@@ -47,8 +47,8 @@ do { \
 extern void *zalloc
 (long size);
 
-extern void dumpf
-(int indent, const char *msg, ...);
+extern void dumpf (int indent, const char *msg, ...)
+  ATTRIBUTE_PRINTF (2, 3);
 
 extern unsigned target_a2i
 (int ms_bit_nr,

sim/ppc/sim_callbacks.h

@@ -31,9 +31,8 @@
 void sim_io_printf_filtered
 (const char *msg, ...) ATTRIBUTE_PRINTF_1;
 
-void ATTRIBUTE_NORETURN error
-(const char *msg, ...);
-
+extern void error (const char *msg, ...)
+  ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (1, 2);
 
 /* External environment:
 

sim/ppc/sim_calls.c

@@ -388,7 +388,7 @@ sim_io_error (SIM_DESC sd, const char *fmt, ...)
 
 /****/
 
-void ATTRIBUTE_NORETURN
+void
 error (const char *msg, ...)
 {
   va_list ap;